Can you use openID as a single sign-on for an iphone app?

I'm looking to implement Single Sign On for a native iOS app whereby logging in with this single sign on gives the mobile device authenticated access to our private service in a fashion that is somewhat similar to oauth.

The marketing text on openid.net suggests that "OpenID is a safe, faster, and easier way to log in to web sites.". Emphasis on web sites.

So the question is: Is it reasonable to implement openID on a native mobile app, or is openID only for web sites.

I've been scouring the web and I'm not finding a way to fit openID in as my login option.